Design of a vacuum interface of a microsecond timescale HPM diode with guiding magnetic field
-
摘要: 介绍了一种微秒长脉冲有磁场的真空二极管界面的设计和实验结果。采取了三种措施来抑制沿面闪络：一是阴极电子束挡板，用来拦截来自阴极和电子束漂移管的回流电子束；二是接地屏蔽板，使电场等势线和界面成约45°角，使阴极三结合点处发射的电子远离绝缘板；三是降低阴极三结合点处的场强，并使用一悬浮电位的金属环阻止电子倍增过程。计算了二极管内电场、磁场分布和电子束的运动轨迹并据此优化了真空界面的结构，实验验证了该二极管真空界面可以在400 kV、800 ns条件下正常工作，可以支持长脉冲高功率微波器件的研究。Abstract: Long pulse high power pulse driver in the microsecond range is an important platform for conducting high power microwave (HPM) device studies and one of the key technologies is to prohibit surface flashover of the vacuum diode interface under the conditions of long pulse duration and the presence of guiding magnetic field. We report a design of a vacuum interface which works in the microsecond timescale with guiding magnetic field. Three measures are adopted to suppress the surface flashover. First is a cathode electron beam blocker, which intercepts the electron beam from the cathode and electron beam drift tube; Second is a grounded plate field shaper, which makes the electric field equipotential line and the interface form an angle of about 45°, so that the electrons emitted from the triple junction are directed away from the insulator; Third is a floating metal ring, which prevents the electron multiplication if emission from cathode stalk triple junction does occur. The electric field and magnetic field in the diode and the trajectory of electron beam are calculated, and the geometry of the vacuum interface is optimized. Experiments show that the vacuum interface of the diode can work at voltage of 400 kV and pulse width of 800 ns, which allows the study of long pulse high power microwave tubes.
-
Key words:
- pulsed power /
- high power microwave /
- vacuum interface /
- surface flashover /
- vacuum diode
-
图 1 最初设计的的真空二极管结构和实验结果
Figure 1. Original design of the vacuum interface and experimental result
图 3 二极管和真空界面附近的磁场线分布
Figure 3. Magnetic field lines near the vacuum interface and the diode
-
[1] Zhang Jiande, Ge Xingjun, Zhang Jun, et al. Research progresses on Cherenkov and transit-time high-power microwave sources at NUDT[J]. Matter and Radiation at Extremes, 2016, 1(3): 163-178. doi: 10.1016/j.mre.2016.04.001 [2] 杨汉武, 高景明, 张自成, 等. 基于MOV的800纳秒吉瓦级脉冲驱动源[C]//第七届全国脉冲功率会议. 重庆, 2021Yang Hanwu, Gao Jingming, Zhang Zicheng, et al. Test of an 800 ns gigawatt pulse generator based on metal-oxide varistors[C]//Proceedings of the 7th China Pulsed Power Conference. Chongqing, 2021 [3] Wang Hongguang, Zhang Jianwei, Li Yongdong, et al. 2D particle-in-cell simulation of the entire process of surface flashover on insulator in vacuum[J]. Physics of Plasmas, 2018, 25: 043522. doi: 10.1063/1.5021177 [4] Xun Tao, Yang Hanwu, Zhang Jiande. A high-vacuum high-electric-field pulsed power interface based on a ceramic insulator[J]. IEEE Transactions on Plasma Science, 2015, 43(12): 4130-4135. doi: 10.1109/TPS.2015.2497276 [5] Miller H C. Flashover of insulators in vacuum: the last twenty years[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 2015, 22(6): 3641-3657. doi: 10.1109/TDEI.2015.004702 [6] Miller H C. Flashover of insulators in vacuum: review of the phenomena and techniques to improved holdoff voltage[J]. IEEE Transactions on Electrical Insulation, 1993, 28(4): 512-527. doi: 10.1109/14.231534 [7] Krasik Y E, Leopold J G. Initiation of vacuum insulator surface high-voltage flashover with electrons produced by laser illumination[J]. Physics of Plasmas, 2015, 22: 083109. doi: 10.1063/1.4928580 [8] Harris J R. A tutorial on vacuum surface flashover[J]. IEEE Transactions on Plasma Science, 2018, 46(6): 1872-1880. doi: 10.1109/TPS.2017.2759248 [9] Harris J R, Caporaso G J, Blackfield D, et al. Displacement current and surface flashover[J]. Applied Physics Letters, 2007, 91: 121504. doi: 10.1063/1.2785116 [10] Gleizer J Z, Krasik Y E, Dai U, et al. Vacuum surface flashover: experiments and simulations[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 2014, 21(5): 2394-2404. doi: 10.1109/TDEI.2014.004628 [11] Smith I D. Flashover of vacuum interfaces with many stages and large transit times[J]. IEEE Transactions on Plasma Science, 1997, 25(2): 293-299. doi: 10.1109/27.602502 [12] Sun Xiaoliang, Xun Tao, Zhong Huihuang, et al. Characterization of flashover plasma across a large-scale ceramic vacuum interface initiated by explosive electron emission[J]. AIP Advances, 2018, 8: 075309. doi: 10.1063/1.5039434 [13] 刘瑜, 邓建军, 王勐, 等. 外加磁场下真空沿面闪络特性数值模拟[J]. 强激光与粒子束, 2010, 22(10):2501-2504. (Liu Yu, Deng Jianjun, Wang Meng, et al. Numerical simulation of vacuum surface flashover under applied magnetic field[J]. High Power Laser and Particle Beams, 2010, 22(10): 2501-2504 doi: 10.3788/HPLPB20102210.2501Liu Yu, Deng Jianjun, Wang Meng, et al. Numerical simulation of vacuum surface flashover under applied magnetic field[J]. High Power Laser and Particle Beams, 2010, 22(10): 2501-2504 doi: 10.3788/HPLPB20102210.2501 [14] Savage M E, Stoltzfus B S, Austin K N, et al. Performance of a radial vacuum insulator stack[C]//Proceedings of 2015 IEEE Pulsed Power Conference. 2015: 1-6. [15] Mesyats G A, Korovin S D, Gunin A V, et al. Repetitively pulsed high-current accelerators with transformer charging of forming lines[J]. Laser and Particle Beams, 2003, 21(2): 197-209. doi: 10.1017/S0263034603212076 -
下载:
点击查看大图
图(6)
计量
- 文章访问数: 821
- HTML全文浏览量: 239
- PDF下载量: 82
- 被引次数: 0
